drm/i915: Convert i915_wait_seqno to i915_wait_request

Updated i915_wait_seqno() to take a request structure instead of a seqno value
and renamed it accordingly. Internally, it just pulls the seqno out of the
request and calls on to __wait_seqno() as before. However, all the code further
up the stack is now simplified as it can just pass the request object straight
through without having to peek inside.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
[danvet: Squash in hunk from an earlier patch which was rebased
wrongly.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 2f944c4..8d0b8ac 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -922,7 +922,6 @@
 {
 	struct intel_engine_cs *ring = ringbuf->ring;
 	struct drm_i915_gem_request *request;
-	u32 seqno = 0;
 	int ret;
 
 	if (ringbuf->last_retired_head != -1) {
@@ -947,15 +946,14 @@
 		/* Would completion of this request free enough space? */
 		if (__intel_ring_space(request->tail, ringbuf->tail,
 				       ringbuf->size) >= bytes) {
-			seqno = request->seqno;
 			break;
 		}
 	}
 
-	if (seqno == 0)
+	if (&request->list == &ring->request_list)
 		return -ENOSPC;
 
-	ret = i915_wait_seqno(ring, seqno);
+	ret = i915_wait_request(request);
 	if (ret)
 		return ret;